Page 122 - ebook HCC

EASL HCC SUMMITHCC SUMMIT
GENEVA, SWITZERLANDA, SWITZERLAND
PROGRAMME
121
120 PROGRAMME AND ABSTRACTSAND ABSTRACTS GENEV EASL 121
120
FEBRUARY 13 - 16, 2014Y 13 - 16, 2014
FEBRUAR
Poster Board Number B18 Poster Board Number B19
CONTROL OF HEPATIC STELLATE CELLS OF
LIVER HEALTH AND DISEASE EPIGENETIC REPROGRAMMING MODULATES
MALIGNANT PROPERTIES OF HUMAN LIVER
CANCER CELLS
Carolin Mogler , Matthias Wieland , Junhao Hu , Anja Runge ,
1 2
2
2
2
Vijayshankar Sivanandam , Claudia Korn , Tabea Arnsperger , André Neumann , 1 1 1 1
3
2
2
2
Thomas Longerich , Peter Schirmacher , Hellmut Augustin 2 Chiara Raggi , Valentina M. Factor , Daekwan Seo , Matthew C. Gillen ,
1
1
1
1
1
1
2
3
1 Institue of pathology, DKFZ, Division of Vascular Biology and Tumor Angiogenesis, Agnes Holczbauer , Jens U. Marquardt , Jesper B. Andersen , Snorri S. Thorgeirsson
Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National
1
Medical Faculty Mannheim , Heidelberg, Germany Cancer Institute, NIH, Bethesda, United States
Corresponding author’s e-mail: carolin.mogler@med.uni-heidelberg.de Corresponding author’s e-mail: chiara.raggi@humanitasresearch.it
Introduction: Modulation of cellular fate in solid tumors is defined to a large extent by
Introduction: Endosialin is expressed by tumor-associated pericytes and stromal DNMT1-regulated epigenetic machinery and cellular and non-cellular constituents in the
myofibroblasts, identifying it as a marker of the activated mesenchymal lineage. tumor-initiating cells (TICs) niche.
Aims: We consequently hypothesized that Endosialin may be functionally involved Aims: Current study examines the significance of the DNMT1-cellular interactions in
in organ fibrosis, a process critically dependent on the recruitment and proliferation of reprogramming of TICs properties.
activated mesenchymal cells.
BASIC POSTER ABSTRACTS Results: In line with this hypothesis, expression profiling experiments of human liver tissue and exposed to a transient nontoxic dose of a DNMT1-inhibitor Zebularine (ZEB). After a BASIC POSTER ABSTRACTS
Methodology: Seven HCC cell lines were plated in 2D culture at various cell densities
3-day treatment, cells were cultured in 3D non-adherent condition in ZEB- and serum-free
samples revealed that Endosialin expression was significantly upregulated during liver
media to generate primary spheres (G1) which were then passaged through generation
fibrosis and cirrhosis. Endosialin expression was most pronounced in portal fibroblasts and
G5. Differences in long-term self-renewal, gene expression, tumorigenicity and metastatic
potential of G1-G5 spheres were examined.
hepatic stellate cells (HSC), which localized along the sinusoids in the space of Dissé and
also forming scar tissue of fibrotic septa and cirrhotic nodules. To mechanistically study
the role of Endosialin during liver fibrogenesis, we pursued CCl -induced liver fibrosis
responses in 5/7 tested HCC cell lines. In cells grown at low density (LD), ZEB caused a
4
experiments in wildtype and Endosialin-deficient mice. CCl -mediated liver damage was Results: Transient exposure to ZEB produced the differential cell density-depended
remarkable increase in G1 sphere formation. This effect persisted through G5. In striking
4
similar in both genotypes. Surprisingly though, hepatocyte proliferation during early stages contrast, untreated LD cells failed to form primary spheres while the sphere forming
of liver fibrosis was significantly elevated in the absence of Endosialin. To study proliferative potential of high density (HD) and HD ZEB-treated (HDZ) cells rapidly decreased over
liver regeneration more directly, we pursued partial hepatectomy experiments and traced the first 3 generations. Likewise DNMT1 depletion by shRNA promoted acquisition of
hepatocyte proliferation during the rapid phase of liver regeneration. Proliferation of self-renewal potential in LD cells. The increase in sphere forming potential of LDZ cells
hepatocytes during early liver regeneration was dramatically enhanced in Endosialin- strongly correlated with a stable overexpression of cancer stem cell-related markers and
key genes involved in self-renewal and epithelial-mesenchymal transition. Moreover, when
deficient mice suggesting a role of Endosialin in the regulation of proliferative processes. dissociated LDZ, HD and HDZ spheres were injected subcutaneously into NOD/SCID mice,
Subsequently, Endosialin deficient mice were crossed into a virus inducible mouse LDZ cells generated tumors more rapidly and were more metastatic. Both gene reactivation
model of hepatocellular carcinoma (HCC) to investigate the onset and the progression and tumorigenicity progressively increased from G1 to G4. Tumors derived from G1-G4
of hepatocarcinogenesis. According to our results Endosialin deficiency resulted in more LDZs were also increasingly more vascular. Global transcriptome analysis of LDZ spheres
detectable tumor nodules and higher overall tumor burden. at G1-G4 confirmed that a LDZ signature was enriched in genes associated with oncogenic
signaling pathways and could predict clinical outcome of liver cancer patients.
Conclusions: We therefore postulate that Endosialin on HSC might function as negative Conclusions: DNMT1 inhibition combined with cellular context-dependent cues results in
regulator of liver cell proliferation. reprogramming of hepatic TICs which persists long after the drug removal and affects their
fate. These findings may provide a new venue for therapeutic strategy in HCC patients.